feat: add alerting API and types

Add alert types (AlertType, AlertEvent, AlertDetails) and the GetAlerts
admin API for retrieving license and certificate expiry alerts.

Author: Praveenrajmani

alert.go

@@ -0,0 +1,125 @@
+// Copyright (c) 2015-2026 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package madmin
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+	"iter"
+	"net/http"
+	"time"
+)
+
+// AlertType represents the type of alert event
+type AlertType string
+
+const (
+	// AlertTypeLicense represents license expiration alerts
+	AlertTypeLicense AlertType = "license-expiry"
+	// AlertTypeCertificate represents TLS certificate expiration alerts
+	AlertTypeCertificate AlertType = "certificate-expiry"
+)
+
+// Alert represents a single alert event in the system.
+// It captures alert information with contextual metadata including deployment and cluster information.
+type Alert struct {
+	Type         AlertType    `json:"type"`
+	Timestamp    time.Time    `json:"timestamp"`
+	Title        string       `json:"title"`
+	Message      string       `json:"message"`
+	Details      AlertDetails `json:"details"`
+	DeploymentID string       `json:"deploymentId"`
+	ClusterName  string       `json:"clusterName"`
+}
+
+// AlertDetails is a strongly-typed union for alert-specific details.
+// Only one field should be populated based on the alert type.
+type AlertDetails struct {
+	LicenseExpiry     *LicenseExpiryDetails     `json:"licenseExpiry,omitempty"`
+	CertificateExpiry *CertificateExpiryDetails `json:"certificateExpiry,omitempty"`
+}
+
+// LicenseExpiryDetails contains license-specific alert information.
+type LicenseExpiryDetails struct {
+	LicenseID string    `json:"licenseId"`
+	ExpiresAt time.Time `json:"expiresAt"`
+	State     string    `json:"state"` // "expiring_soon", "grace_period", "read_only", "fully_expired"
+}
+
+// CertificateExpiryDetails contains certificate-specific alert information.
+type CertificateExpiryDetails struct {
+	CommonName      string    `json:"commonName"`
+	SerialNumber    string    `json:"serialNumber"`
+	NotAfter        time.Time `json:"notAfter"`
+	DaysUntilExpiry int       `json:"daysUntilExpiry"`
+	DNSNames        []string  `json:"dnsNames"`
+}
+
+// AlertLogOpts represents options for querying alerts
+type AlertLogOpts struct {
+	Types      []string      `json:"types,omitempty"`
+	Interval   time.Duration `json:"interval,omitempty"`
+	MaxPerNode int           `json:"maxPerNode,omitempty"`
+}
+
+// GetAlerts returns alerts stored in the system as a streaming JSON response
+// via POST /admin/alerts. Use AlertLogOpts.Interval to control the server-side
+// check interval.
+func (adm AdminClient) GetAlerts(ctx context.Context, opts AlertLogOpts) iter.Seq2[*Alert, error] {
+	return func(yield func(*Alert, error) bool) {
+		alertOpts, err := json.Marshal(opts)
+		if err != nil {
+			yield(nil, err)
+			return
+		}
+		reqData := requestData{
+			relPath: adminAPIPrefix + "/alerts",
+			content: alertOpts,
+		}
+		resp, err := adm.executeMethod(ctx, http.MethodPost, reqData)
+		if err != nil {
+			yield(nil, err)
+			return
+		}
+		defer closeResponse(resp)
+		if resp.StatusCode != http.StatusOK {
+			yield(nil, httpRespToErrorResponse(resp))
+			return
+		}
+		dec := json.NewDecoder(resp.Body)
+		for {
+			var alert Alert
+			if err = dec.Decode(&alert); err != nil {
+				if errors.Is(err, io.EOF) {
+					break
+				}
+				continue
+			}
+			select {
+			case <-ctx.Done():
+				return
+			default:
+				if !yield(&alert, nil) {
+					return
+				}
+			}
+		}
+	}
+}

parse-config.go

@@ -88,6 +88,10 @@ const (
 	LogAPIKafkaSubSys   = "log_api_kafka"
 	LogErrorKafkaSubSys = "log_error_kafka"
 	LogAuditKafkaSubSys = "log_audit_kafka"
+
+	AlertInternalSubSys = "alert_internal"
+	AlertWebhookSubSys  = "alert_webhook"
+	AlertKafkaSubSys    = "alert_kafka"
 )
 
 // SubSystems - list of all subsystems in MinIO
@@ -186,6 +190,9 @@ var EOSSubSystems = set.CreateStringSet(
 	LogAPIKafkaSubSys,
 	LogErrorKafkaSubSys,
 	LogAuditKafkaSubSys,
+	AlertInternalSubSys,
+	AlertWebhookSubSys,
+	AlertKafkaSubSys,
 )
 
 // Standard config keys and values.